In this experiment you will replicate (with modern instrumentation) the classic experiment first performed by Hans Geiger and Ernest Marsden in 1909, under the direction of Ernest Rutherford. Previous to this experiment the generally accepted model of the atom was that of a “plum-pudding” with the positive charge spread out over a sphere and discrete negative charges spread throughout. The deflection of positively charged alpha particles incident on a thin gold foil showed conclusively that this model was incorrect and that much more likely, the positive charge was concentrated in a tiny volume with the negative charges surrounding it at a distance. This experiment uses modern instrumentation and is like doing experiments in high energy physics. Set aside two full days in advance of the start of your experiment to do the non trivial Pre-Lab!

Glossary RUTHERFORD SCATTERING is a phenomenon that was first explained by Ernest Rutherford in 1911, leading to the development of the Rutherford model of the atom and eventually the Bohr model.